Pixel, method of manufacturing the same, and image processing devices including the same

ABSTRACT

A pixel of an image sensor includes a color filter configured to pass visible wavelengths, and an infrared cut-off filter disposed on the color filter configured to cut off infrared wavelengths.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119 to Korean PatentApplication No. 10-2010-0086235, filed on Sep. 3, 2010, the disclosureof which is incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present invention relates to an image sensor, and more particularly,to a pixel in an image sensor, a method of manufacturing the pixel, andimage processing devices including the same.

2. Discussion of the Related Art

Image sensors use long wavelengths to simultaneously detect color imageinformation and depth information of an object. For example, depthsensors detect depth information of an object using an infrared filter.

A color filter disposed on pixels in a depth sensor passes infraredwavelengths as well as visible wavelengths. As a result of the passingof infrared wavelengths by the color filter, color crosstalk may occur.

SUMMARY

According to exemplary embodiments of the present inventive concept, apixel includes an infrared cut-off filter disposed on a color filterwhich blocks infrared wavelengths, thereby preventing or reducing colorcrosstalk that may be caused by the color filter. Exemplary embodimentsfurther include a method of manufacturing the pixel, and imageprocessing devices including the same.

According to exemplary embodiments of the present inventive concept, apixel of an image sensor includes a color filter configured to passvisible wavelengths, and an infrared cut-off filter disposed on thecolor filter configured to cut off infrared wavelengths.

The color filter may be a red filter, a blue filter, or a green filter.Alternatively, the color filter may be a cyan filter, a yellow filter,or a magenta filter.

According to exemplary embodiments of the present inventive concept, apixel array of an image sensor includes a first pixel of a first pixeltype and a second pixel of a second pixel type. The first pixel includesa color filter configured to pass visible wavelengths, and an infraredcut-off filter disposed on the color filter configured to cut offinfrared wavelengths. The second pixel includes an infrared filterconfigured to pass the infrared wavelengths.

The color filter may be a red filter, a blue filter, or a green filter.Alternatively, the color filter may be a cyan filter, a yellow filter,or a magenta filter.

According to an exemplary embodiment of the present inventive concept,an image processing device includes the above-described image sensor anda processor configured to control an operation of the image sensor.

According to an exemplary embodiment of the present inventive concept, amethod of manufacturing a pixel array of an image sensor includesforming a plurality of unit pixel circuits for each of a plurality ofpixels on a substrate, forming a dielectric layer on the unit pixelcircuits, forming a color filter and an infrared filter on thedielectric layer, forming an infrared cut-off filter on the color filterand the infrared filter, etching the infrared cut-off filter formed onthe infrared filter, and forming a microlens on the infrared cut-offfilter and the infrared filter. The color filter is formed on pixels ofa first pixel type and the infrared filter is formed on pixels of asecond pixel type. The color filter is configured to pass visiblewavelengths. The infrared filter is configured to pass infraredwavelengths. The infrared cut-off filter is configured to cut offinfrared wavelengths.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the present inventive concept willbecome more apparent by describing in detail exemplary embodimentsthereof with reference to the accompanying drawings, in which:

FIG. 1 is a cross-sectional view of a pixel array according to anexemplary embodiment of the present inventive concept;

FIG. 2 is a circuit diagram of a unit pixel circuit illustrated in FIG.1 according to an exemplary embodiment of the present inventive concept;

FIG. 3 is a plan view of the pixel array illustrated in FIG. 1 accordingto an exemplary embodiment of the present inventive concept;

FIG. 4 is a cross-sectional view of a pixel array according to anexemplary embodiment of the present inventive concept;

FIG. 5 is a plan view of the pixel array illustrated in FIG. 4 accordingto an exemplary embodiment of the present inventive concept;

FIG. 6 is a block diagram of an image sensor including the pixel arrayillustrated in FIG. 1 or 4 according to an exemplary embodiment of thepresent inventive concept;

FIG. 7 is a block diagram of an image sensor including the pixel arrayillustrated in FIG. 1 or 4 according to an exemplary embodiment of thepresent inventive concept;

FIG. 8 is a block diagram of an image processing device including theimage sensor illustrated in FIG. 6 or 7 according to an exemplaryembodiment of the present inventive concept; and

FIG. 9 is a flowchart of a method of manufacturing a pixel for an imagesensor including the pixel array illustrated in FIG. 1 according to anexemplary embodiment of the present inventive concept.

DETAILED DESCRIPTION

Exemplary embodiments of the present inventive concept will be describedmore fully hereinafter with reference to the accompanying drawings. Likereference numerals may refer to like elements throughout theaccompanying drawings.

It will be understood that although the terms first, second, etc. may beused herein to describe various elements, these elements should not belimited by these terms. These terms are only used to distinguish oneelement from another. For example, a first signal could be termed asecond signal, and, similarly, a second signal could be termed a firstsignal without departing from the teachings of the disclosure.

FIG. 1 is a cross-sectional view of a pixel array 10 according to anexemplary embodiment of the present inventive concept. The pixel array10 includes pixels of a first pixel type and a second pixel type. In thepixel array 10, a first pixel 20, a second pixel 30, and a third pixel50 are pixels of the first pixel type, and a fourth pixel 40 is of thesecond pixel type. The pixel array 10 further includes a unit pixelcircuit area 68 disposed at each pixel, a dielectric layer 67 formed oneach pixel, a color filter 65 formed on the first through third pixels20, 30, and 50, an infrared filter 45 formed on the fourth pixel 40, aninfrared cut-off filter 63 formed on the first through third pixels 20,30, and 50, a planarization layer 62 formed on each pixel, and amicrolens 61 disposed on each pixel. The color filter 65 includes a redfilter 25 formed on the first pixel 20, a green filter 35 formed on thesecond pixel 30, and a blue filter 55 formed on the third pixel 50. Theinfrared cut-off filter 63 includes an infrared cut-off filter 23 formedon the first pixel 20, an infrared cut-off filter 33 formed on thesecond pixel 30, and an infrared cut-off filter 53 formed on the thirdpixel 50. Pixels of the first pixel type, including the first pixel 20,the second pixel 30, and the third pixel 50, have a substantiallysimilar structure. Thus, the first pixel type is described herein withreference to the first pixel 20.

The first pixel 20 includes a microlens 61, an infrared cut-off filter23, a color filter 65, a dielectric layer 67, and a unit pixel circuitarea 68. In an exemplary embodiment, the first pixel 20 does not includethe microlens 61. The microlens 61 collects incident light.

The infrared cut-off filter 23 is disposed on the color filter 65 andcuts off wavelengths in the infrared region (hereinafter referred to as“infrared wavelengths”). Accordingly, the first pixel 20 cuts off theinfrared wavelengths, which may prevent or reduce color crosstalk thatmay be caused by the color filter 65. The color filter 65 passes (e.g.,transmits) wavelengths in the visible region (hereinafter referred to as“visible wavelengths”).

In an exemplary embodiment, the color filter 65 of the first pixel 20 isa red filter 25. The red filter 25 passes red wavelengths among thevisible wavelengths passed by the infrared cut-off filter 23 of thefirst pixel 20. The color filter 65 of the second pixel 30 is a greenfilter 35. The green filter 35 passes green wavelengths among thevisible wavelengths passed by the infrared cut-off filter 33 of thesecond pixel 30. The color filter 65 of the third pixel 50 is a bluefilter 55. The blue filter 55 passes blue wavelengths among the visiblewavelengths passed by the infrared cut-off filter 53 of the third pixel50.

The dielectric layer 67 is disposed between the color filter 65 and theunit pixel circuit area 68. The dielectric layer 67 may be formed of,for example, an oxide layer or a composite layer of an oxide layer and anitride layer, however the dielectric layer 67 is not limited thereto.The unit pixel circuit area 68 is an area in which a unit pixel circuitis disposed.

FIG. 2 is a circuit diagram of a unit pixel circuit 70 disposed in theunit pixel circuit area 68 illustrated in FIG. 1. Referring to FIGS. 1and 2, the unit pixel circuit 70 includes a photoelectric conversionelement 71, a reset transistor RX, a transfer transistor TX, a drivetransistor DX, and a selection transistor SX.

The photoelectric conversion element 71 generates photons in response toincident light. The photoelectric conversion element 71 may be, forexample, a photodetector including a photo diode, a photo transistor, aphoto gate, or a pinned photo diode (PPD), however the photoelectricconversion element 71 is not limited thereto.

The reset transistor RX resets a floating diffusion region FD inresponse to a reset signal RG. The transfer transistor TX transmitsphotocharges generated by the photoelectric conversion element 71 to thefloating diffusion region FD in response to a transfer signal TG. Thedrive transistor DX functions as a source follower buffer amplifier. Forexample, the drive transistor DX performs buffering in response to thephotocharges in the floating diffusion region FD. The selectiontransistor SX selects a unit pixel which will output a pixel signaloutput from the drive transistor DX in response to a selection signalSEL, and outputs the pixel signal to a column line COL.

In the exemplary embodiment illustrated in FIG. 2, the unit pixelcircuit 70 includes a single photoelectric conversion element 71 andfour transistors TX, RX, DX, and SX, however the present inventiveconcept is not limited thereto.

Referring to FIG. 1, according to an exemplary embodiment, the pixelarray 10 may also include a planarization layer 62. The planarizationlayer 62 allows the microlens 61 to be foamed on a substantially smoothand even surface. The planarization layer 62 may be made using, forexample, an acrylic or epoxy material, however the planarization layer62 is not limited thereto. The planarization layer 62 may not beutilized when the surface of the infrared cut-off filter 23 is even orhas been polished. The thickness of the planarization layer 62 on thefourth pixel 40 may be greater than the thickness of the planarizationlayer on the first through third pixels 20, 30, and 50 since the fourthpixel 40 does not include an infrared cut-off filter and theplanarization layer is formed on the infrared filter 45. The secondpixel 30 and the third pixel 50 have a substantially similar structureas the first pixel 20, except for having different color filters (e.g.,the second pixel 30 includes a green filter 35 and the third pixel 50includes a blue filter 55).

The fourth pixel 40 of a second pixel type includes a microlens 61, aninfrared filter 45, a dielectric layer 67, and a unit pixel circuit area68. The infrared filter 45 passes only infrared wavelengths among thewavelengths of light passing through the microlens 61. The second pixeltype is described herein with reference to the fourth pixel 40.

In the fourth pixel 40, the dielectric layer 67 is disposed between theinfrared filter 45 and the unit pixel circuit area 68. The dielectriclayer 67 may be formed of for example, an oxide layer or a compositelayer of an oxide layer and a nitride layer, however the dielectriclayer 67 is not limited thereto. The unit pixel circuit area 68 is anarea in which a unit pixel circuit is disposed. The function andoperation of the unit pixel circuit area 68 of the fourth pixel 40 arethe same as the function and operation of the unit pixel circuit area 68of the first pixel 20. Thus, descriptions thereof are omitted.

FIG. 3 is a plan view of the pixel array 10 illustrated in FIG. 1.Referring to FIGS. 1-3, the pixel array 10 includes pixels of a firstpixel type and a second pixel type.

In an exemplary embodiment, the first pixel 20, the second pixel 30, andthe third pixel 50 are of the first pixel type. The first pixel 20includes the infrared cut-off filter 23 and the red filter 25. Theinfrared cut-off filter 23 cuts off the infrared wavelengths and passesthe visible wavelengths, and the red filter 25 passes the redwavelengths among the visible wavelengths passed by the infrared cut-offfilter 23. The second pixel 30 includes the infrared cut-off filter 33and the green filter 35. The infrared cut-off filter 33 cuts off theinfrared wavelengths and passes the visible wavelengths, and the greenfilter 35 passes the green wavelengths among the visible wavelengthspassed by the infrared cut-off filter 33. The third pixel 50 includesthe infrared cut-off filter 53 and the blue filter 55. The infraredcut-off filter 53 cuts off the infrared wavelengths and passes thevisible wavelengths, and the blue filter 55 passes the blue wavelengthsamong the visible wavelengths passed by the infrared cut-off filter 53.

Pixels of the first pixel type include infrared cut-off filters andcolor filters. For example, the first through third pixels 20, 30, and50 include the infrared cut-off filters 23, 33, and 53, and the colorfilters 25, 35, and 55, respectively. The infrared cut-off filters 23,33 and 53 may prevent or reduce color crosstalk that may be caused bythe color filters 25, 35, and 55. Pixels of the second pixel typeinclude an infrared filter. For example, the fourth pixel 40 includesthe infrared filter 45. The infrared filter 45 passes only the infraredwavelengths. As will be appreciated by one having ordinary skill in theart, the layout pattern of pixels of the first pixel type (e.g., thefirst through third pixels 20, 30, and 50) and pixels of the secondpixel type (e.g., the fourth pixel 40) is not limited to the exemplaryembodiments illustrated in FIGS. 1 and 3.

FIG. 4 is a cross-sectional view of a pixel array 10-1 according to anexemplary embodiment of the present inventive concept. Referring to FIG.4, the pixel array 10-1 includes a first pixel type and a second pixeltype.

In the pixel array 10-1, a first pixel 20-1, a second pixel 30-1, and athird pixel 50-1 are pixels of the first pixel type, and a fourth pixel40-1 is of the second pixel type. The pixel array 10-1 further includesa unit pixel circuit area 68-1 disposed at each pixel, a dielectriclayer 67-1 formed on each pixel, a color filter 65-1 formed on the firstthrough third pixels 20-1, 30-1, and 50-1, an infrared filter 45-1formed on the fourth pixel 40-1, an infrared cut-off filter 63-1 formedon the first through third pixels 20-1, 30-1, and 50-1, a planarizationlayer 62-1 formed on each pixel, and a microlens 61-1 disposed on eachpixel. The color filter 65-1 includes a cyan filter 25-1 formed on thefirst pixel 20-1, a magenta filter 35-1 formed on the second pixel 30-1,and a yellow filter 55-1 formed on the third pixel 50-1. The infraredcut-off filter 63-1 includes an infrared cut-off filter 23-1 formed onthe first pixel 20-1, an infrared cut-off filter 33-1 formed on thesecond pixel 30-1, and an infrared cut-off filter 53-1 formed on thethird pixel 50-1. Pixels of the first pixel type, including the firstpixel 20-1, the second pixel 30-1, and the 3rd pixel 50-1 have asubstantially similar structure. Thus, the first pixel type is describedherein with reference to the first pixel 20-1.

The first pixel 20-1 includes a microlens 61-1, an infrared cut-offfilter 23-1, a color filter 65-1, a dielectric layer 67-1, and a unitpixel circuit area 68-1. The function and operation of the microlens61-1, the infrared cut-off filter 23-1, the dielectric layer 67-1, andthe unit pixel circuit area 68-1 are the same as the function of themicrolens 61, the infrared cut-off filter 23, the dielectric layer 67,and the unit pixel circuit area 68 illustrated in FIG. 1, respectively.Thus, descriptions thereof are omitted. In an exemplary embodiment, thepixel array 10-1 may also include a planarization layer 62-1. Thefunction and operation of the planarization layer 62-1 are the same asthe function and operation of the planarization layer 62 illustrated inFIG. 1. Thus, a description thereof is omitted.

In an exemplary embodiment, the first pixel 20-1 does not include themicrolens 61-1. The microlens 61-1 collects incident light.

The color filter 65-1 passes certain visible wavelengths. For example,the color filter 65-1 of the first pixel 20-1 is a cyan filter 25-1. Thecyan filter 25-1 passes wavelengths ranging from about 450 nm to about550 nm among the visible wavelengths passed by the infrared cut-offfilter 23-1 of the first pixel 20-1. The color filter 65-1 of the secondpixel 30-1 is a magenta filter 35-1. The magenta filter 35-1 passeswavelengths ranging from about 400 nm to about 480 nm among the visiblewavelengths passed by the infrared cut-off filter 33-1 of the secondpixel 30-1. The color filter 65-1 of the third pixel 50-1 is a yellowfilter 55-1. The yellow filter 55-1 passes wavelengths ranging fromabout 500 nm to about 600 nm among the visible wavelengths passed by theinfrared cut-off filter 53-1 of the third pixel 50-1. The fourth pixel40-1 of the second pixel type includes an infrared filter 45-1. Theinfrared filter 45-1 passes only infrared wavelengths among thewavelengths of light passing through the microlens 61-1.

FIG. 5 is a plan view of the pixel array 10-1 illustrated in FIG. 4.Referring to FIGS. 4 and 5, the pixel array 10-1 includes pixels of afirst pixel type and a second pixel type. The first pixel 20-1, thesecond pixel 30-1, and the third pixel 50-1 are of the first pixel type,and the fourth pixel 40-1 is of the second pixel type.

The first pixel 20-1 includes the infrared cut-off filter 23-1 and thecyan filter 25-1. The second pixel 30-1 includes the infrared cut-offfilter 33-1 and the magenta filter 35-1. The third pixel 50-1 includesthe infrared cut-off filter 53-1 and the yellow filter 55-1.

Pixels of the first pixel type include infrared cut-off filters andcolor filters. For example, the first through third pixels 20-1, 30-1,and 50-1 include the infrared cut-off filters 23-1, 33-1, and 53-1, andthe color filters 25-1, 35-1, and 55-1, respectively. The infraredcut-off filters 23-1, 33-1, and 53-1 may prevent or reduce colorcrosstalk that may be caused by the color filters 25-1, 35-1, and 55-1.

Pixels of the second pixel type include an infrared filter. For example,the fourth pixel 40-1 includes the infrared filter 45-1. The infraredfilter 45-1 passes only the infrared wavelengths. As will be appreciatedby one having ordinary skill in the art, the layout pattern of pixels ofthe first pixel type (e.g., the first through third pixels 20-1, 30-1,and 50-1) and pixels of the second pixel type (e.g., the fourth pixel40-1) is not limited to the exemplary embodiments illustrated in FIGS. 4and 5.

FIG. 6 is a block diagram of an image sensor 200-1 including the pixelarray 10 or 10-1 illustrated in FIGS. 1 and 4 according to exemplaryembodiments of the present inventive concept. The image sensor 200-1includes a photoelectric conversion circuit 110-1 and an image signalprocessor (ISP) 135-1. The photoelectric conversion circuit 110-1 andthe ISP 135-1 may be implemented on separate chips, respectively, or ona single chip.

The photoelectric conversion circuit 110-1 generates an image signal ofan object based on incident light. The photoelectric conversion circuit110-1 includes a pixel array 111-1, a row decoder 113-1, a row driver115-1, a correlated double sampling (CDS) block 117-1, an analogselector 119-1, an amplifier 121-1, an analog-to-digital converter (ADC)123-1, a column driver 125-1, a column decoder 127-1, a timing generator129-1, and a control register block 131-1.

The pixel array 111-1 may include a plurality of pixels connected with aplurality of row lines and a plurality of column lines in a matrix form.The pixel array 111-1 may be the pixel array 10 illustrated in FIGS. 1and 3 or the pixel array 10-1 illustrated in FIGS. 4-5. For example, theplurality of pixels in the pixel array 111-1 may include pixels of thefirst pixel type and the second pixel type as described with referenceto FIGS. 1 and 3, or pixels of the first pixel type and the second pixeltype as described with reference to FIGS. 4-5. Pixels of the first pixeltype respectively include infrared cut-off filters, which may prevent orreduce color crosstalk that may be caused by the color filters of thepixels.

The row decoder 113-1 decodes a row control signal (e.g., an addresssignal) generated by the timing generator 129-1. The row driver 115-1selects at least one row line among the plurality of row lines in thepixel array 111-1 in response to a decoded row control signal.

The CDS block 117-1 performs CDS on a pixel signal output from a unitpixel connected to one of the plurality of column lines in the pixelarray 111-1, and outputs sampling signals. The analog selector 119-1selectively outputs one of the sampling signals output from the CDSblock 117-1 in response to a column control signal (e.g., an addresssignal) output from the column driver 125-1.

The column driver 125-1 selectively activates one of the column lines inthe pixel array 111-1 in response to a decoded control signal (e.g., adecoded address signal) output from the column decoder 127-1. The columndecoder 127-1 decodes a control signal (e.g., an address signal)generated by the timing generator 129-1.

The amplifier 121-1 amplifies a signal output from the analog selector119-1. The ADC 123-1 converts a signal output from the amplifier 121-1into a digital signal and outputs the digital signal to the ISP 135-1.

The timing generator 129-1 generates a control signal for controllingthe operation of at least one of the pixel array 111-1, the row decoder113-1, and the column decoder 127-1, based on a command output from thecontrol register block 131-1. The control register block 131-1 generatesa variety of commands for controlling the elements of the photoelectricconversion circuit 110-1. The ISP 135-1 generates an image of an objectbased on pixel signals output from the photoelectric conversion circuit110-1.

FIG. 7 is a block diagram of an image sensor 200-2 including the pixelarray 10 or 10-1 illustrated in FIGS. 1 and 4 according to an exemplaryembodiment of the present inventive concept. The image sensor 200-2includes a photoelectric conversion circuit 110-2 and an ISP 135-2. Thephotoelectric conversion circuit 110-2 and the ISP 135-2 may beimplemented on separate chips, respectively, or on a single chip.

The photoelectric conversion circuit 110-2 generates an image signal ofan object based on incident light. The photoelectric conversion circuit110-2 includes a pixel array 111-2, a row decoder 113-2, a row driver115-2, a CDS block 117-2, an ADC 119-2, an output buffer 121-2, a columndriver 125-2, a column decoder 127-2, a timing generator 129-2, acontrol register block 131-2, and a ramp generator 133-2.

The function and operation of the pixel array 111-2, the row decoder113-2, the row driver 115-2, the CDS block 117-2, and the column decoder127-2 are the same as the function and operation of the pixel array111-1, the row decoder 113-1, the row driver 115-1, the CDS block 117-1,and the column decoder 127-1 illustrated in FIG. 6. Thus, descriptionsthereof are omitted.

The ADC 119-2 compares a signal output from the CDS block 117-2 with aramp signal Vramp received from the ramp generator 133-2, and outputs adigital signal corresponding to a result of the comparison. The outputbuffer 121-2 buffers and outputs the digital signal output from the ADC119-2 in response to a column control signal (e.g., an address signal)output from the column driver 125-2.

The timing generator 129-2 generates a control signal for controllingthe operation of at least one of the pixel array 111-2, the row decoder113-2, the output buffer 121-2, the column decoder 127-2, and the rampgenerator 133-2 based on a command output from the control registerblock 131-2. The ramp generator 133-2 outputs the ramp signal Vramp tothe CDS block 117-2 in response to the command output from the controlregister block 131-2. The ISP 135-2 generates an image of an objectbased on pixel signals output from the photoelectric conversion circuit110-2.

FIG. 8 is a block diagram of an image processing device 300 including animage sensor 200. The image sensor 200 is the image sensor 200-1 or200-2 illustrated in FIGS. 6 and 7 according to exemplary embodiments ofthe present inventive concept. The image processing device 300 may be,for example, a digital camera, a cellular phone equipped with a digitalcamera, or any other electronic device equipped with a digital camera.

The image processing device 300 may process, for example,two-dimensional or three-dimensional image information. The imageprocessing device 300 includes the image sensor 200 and a processor 210controlling the operation of the image sensor 200.

The image processing device 300 may also include an interface (I/F) 230.The I/F 230 may be, for example, an image display device. The imageprocessing device 300 may also include a memory device 220 storingimages and/or video captured by the image sensor 200. The memory device220 may be, for example, a non-volatile memory device which may includea plurality of non-volatile memory cells. The non-volatile memory cellsmay be, for example, electrically erasable programmable read-only memory(EEPROM) cells, flash memory cells, magnetic random access memory (MRAM)cells, spin-transfer torque MRAM cells, conductive bridging RAM (CBRAM)cells, ferroelectric RAM (FeRAM) cells, phase change RAM (PRAM) cellsreferred to as Ovonic unified memory cells, resistive RAM (RRAM orReRAM) cells, nanotube RRAM cells, polymer RAM (PoRAM) cells, nanotubefloating gate memory (NFGM) cells, holographic memory cells, molecularelectronics memory device cells, or insulator resistance change memorycells.

FIG. 9 is a flowchart of a method of manufacturing a pixel for an imagesensor including the pixel array 10 illustrated in FIG. 1 according toan exemplary embodiment of the present inventive concept. The method mayalso be used to manufacture a pixel for an image sensor including thepixel array 10-1 illustrated in FIG. 4. Referring to FIGS. 1 and 9, aunit pixel circuit for each of the first pixel types (e.g., the firstthrough third pixels 20, 30, and 50) and the second pixel type (e.g.,the fourth pixel 40) are formed on a substrate in operation S10. Theunit pixel circuit is implemented in the unit pixel circuit area 68.

The dielectric layer 67 is formed on the unit pixel circuit area 68 inoperation S20. The color filter 65 and the infrared filter 45 are formedon the dielectric layer 67 in operation S30. For example, the red filter25 is formed on the dielectric layer 67 of the first pixel 20, the greenfilter 35 is formed on the dielectric layer 67 of the second pixel 30,the blue filter 55 is formed on the dielectric layer 67 of the thirdpixel 50, and the infrared filter 45 is formed on the dielectric layer67 of the fourth pixel 40. The arrangement of the color filter 65 andthe infrared filter 45 disposed on the dielectric layer 67 is notlimited to the exemplary embodiment illustrated in FIG. 1.

The infrared cut-off filter 63 is formed on the color filter 65 and theinfrared filter 45 in operation S40. The infrared cut-off filter 63formed on the infrared filter 45 is etched in operation S50. As aresult, the infrared cut-off filter 63 is disposed on the first throughthird pixels 20, 30 and 50. The infrared cut-off filter 63 on the firstpixel 20 is the red filter 25, the infrared cut-off filter 63 on thesecond pixel 30 is the green filter 35, and the infrared cut-off filter63 on the third pixel 50 is the blue filter 55. The planarization layer62 may be formed on the infrared cut-off filter 63 and the infraredfilter 45 in operation S60. If the planarization layer 62 is formed, themicrolens 61 is formed on the planarization layer in operation S70. Ifthe planarization layer 62 is not formed, the microlens 61 is formed onthe infrared cut-off filter 63 and the infrared filter 45 in operationS70.

According to exemplary embodiments of the present inventive concept, aninfrared cut-off filter which cuts off the infrared wavelengths isdisposed on a color filter in a pixel of an image processing device. Asa result, color crosstalk that may be caused by the color filter may beprevented or reduced.

While the present inventive concept has been particularly shown anddescribed with reference to the exemplary embodiments thereof, it willbe understood by those of ordinary skill in the art that various changesin form and detail may be made therein without departing from the spiritand scope of the present inventive concept as defined by the followingclaims.

What is claimed is:
 1. A pixel of an image sensor, comprising: a colorfilter configured to pass visible wavelengths; and an infrared cut-offfilter disposed on the color filter configured to cut off infraredwavelengths, wherein the pixel is disposed adjacent to another pixelcomprising an infrared filter configured to pass the infraredwavelengths, and the infrared cut-off filter is disposed on the pixeland is not disposed on the another pixel.
 2. The pixel of claim 1,further comprising: a unit pixel circuit disposed on a substrate; adielectric layer disposed between the unit pixel circuit and the colorfilter; a planarization layer disposed on the infrared cut-off filter;and a microlens disposed on the planarization layer.
 3. The pixel ofclaim 1, wherein the color filter is one of a red filter, a blue filter,or a green filter.
 4. The pixel of claim 3, wherein the red filter isconfigured to pass red wavelengths, the blue filter is configured topass blue wavelengths, and the green filter is configured to pass greenwavelengths.
 5. The pixel of claim 1, wherein the color filter is one ofa cyan filter, a yellow filter, or a magenta filter.
 6. The pixel ofclaim 5, wherein the cyan filter is configured to pass cyan wavelengths,the yellow filter is configured to pass yellow wavelengths, and themagenta filter is configured to pass magenta wavelengths.
 7. A pixelarray of an image sensor, comprising: a first pixel of a first pixeltype comprising a color filter configured to pass visible wavelengthsand a first infrared cut-off filter disposed on the color filterconfigured to cut off infrared wavelengths; and a second pixel of asecond pixel type comprising an infrared filter configured to pass theinfrared wavelengths, wherein the first infrared cut-off filter isdisposed on the first pixel and is not disposed on the second pixel. 8.The pixel array of claim 7, wherein the color filter is one of a redfilter, a blue filter, or a green filter.
 9. The pixel array of claim 8,wherein the red filter is configured to pass red wavelengths, the bluefilter is configured to pass blue wavelengths, and the green filter isconfigured to pass green wavelengths.
 10. The pixel array of claim 7,wherein the color filter is one of a cyan filter, a yellow filter, or amagenta filter.
 11. The pixel array of claim 10, wherein the cyan filteris configured to pass cyan wavelengths, the yellow filter is configuredto pass yellow wavelengths, and the magenta filter is configured to passmagenta wavelengths.
 12. The pixel array of claim 7, further comprising:a third pixel of the first pixel type comprising a green filterconfigured to pass green wavelengths and a second infrared cut-offfilter disposed on the green filter configured to cut off the infraredwavelengths; and a fourth pixel of the first pixel type comprising ablue filter configured to pass blue wavelengths and a third infraredcut-off filter disposed on the blue filter configured to cut off theinfrared wavelengths, wherein the color filter of the first pixel is ared filter configured to pass red wavelengths, wherein the infraredfilter is separate from the blue filter and the red filter, and theinfrared filter is not disposed on the blue filter or the red filter.13. The pixel array of claim 7, further comprising: a third pixel of thefirst pixel type comprising a magenta filter configured to pass magentawavelengths and a second infrared cut-off filter disposed on the magentafilter configured to cut off the infrared wavelengths; and a fourthpixel of the first pixel type comprising a yellow filter configured topass yellow wavelengths and a third infrared cut-off filter disposed onthe yellow filter configured to cut off the infrared wavelengths,wherein the color filter of the first pixel is a cyan filter configuredto pass cyan Wavelengths, wherein the infrared filter is separate fromthe magenta filter, the yellow filter, and the cyan filter, and theinfrared filter is not disposed on the magenta filter, the yellowfilter, or the cyan filter.
 14. The pixel array of claim 13, wherein themagenta filter is configured to pass visible wavelengths ranging fromabout 400 nm to about 480 nm, the yellow filter is configured to passvisible wavelengths ranging from about 500 nm to about 600 nm, and thecyan filter is configured to pass visible wavelengths ranging from about450 nm to about 550 nm.
 15. A method of manufacturing a pixel array ofan image sensor, comprising: forming a color filter and an infraredfilter on a substrate, wherein the color filter is formed on pixels of afirst pixel type and the infrared filter is formed on pixels of a secondpixel type, the color filter is configured to pass visible wavelengths,and the infrared filter is configured to pass infrared wavelengths;forming an infrared cut-off filter on the color filter and the infraredfilter, wherein the infrared cut-off filter is configured to cut offinfrared wavelengths; and etching the infrared cut-off filter formed onthe infrared filter to remove the infrared cut-off filter from theinfrared filter.
 16. The method of claim 15, further comprising: forminga plurality of unit pixel circuits between the substrate and the colorfilter and the infrared filter, wherein each of the unit pixel circuitscorresponds to one of a plurality of pixels; and forming a dielectriclayer between the plurality of unit pixel circuits and the color filterand the infrared filter.
 17. The method of claim 15, further comprising:forming a microlens on the infrared cut-off filter and the infraredfilter.
 18. The method of claim 17, further comprising: forming aplanarization layer between the microlens and the infrared cut-offfilter and the infrared filter.
 19. The method of claim 15, wherein thecolor filter comprises: a red filter formed on a first pixel configuredto pass red wavelengths; a green filter formed on a second pixelconfigured to pass green wavelengths; and a blue filter formed on athird pixel configured to pass blue wavelengths, wherein the infraredfilter is separate from the red filter and the blue filter, and theinfrared filter is not disposed on the red filter or the blue filter.20. The method of claim 15, wherein the color filter comprises: a cyanfilter famed on a first pixel configured to pass cyan wavelengths; amagenta filter formed on a second pixel configured to pass magentawavelengths; and a yellow filter formed on a third pixel configured topass yellow wavelengths, wherein the infrared filter is separate fromthe cyan filter, the magenta filter, and the yellow filter, and theinfrared filter is not disposed on the cyan filter, the magenta filter,or the yellow filter.